Communication networks interconnect data systems so that the data systems may exchange data. Typically, a communication network, hereinafter called network, has transmission paths interconnecting nodes each coupled to data systems and each arranged to write data generated by an originating data system onto the network transmission paths and to read the data off the network transmission paths to a destination data system.
Nodes used with asynchronous networks operate to receive data at an incoming transmission rate from a preceding network node and to transmit data to a subsequent network node at an outgoing transmission rate independent of the incoming transmission rate. Asynchronous network nodes also receive data from data systems coupled with the node and transmit data thereto at transmission rates that may differ from the both the incoming and outgoing transmission rates.
Nodes used with synchronous networks operate to receive clocked incoming data at a constant transmission rate from a preceding network node and to transmit clocked data at an outgoing transmission rate synchronous with the incoming transmission rate to a subsequent network node. Synchronous network nodes also receive clocked data from data systems coupled with the node and transmit clocked data thereto at transmission rates synchronous with both the incoming and outgoing transmission rates.
A problem arises within asynchronous networks in that data systems which could be interconnected by an asynchronous network oftentimes require that clocked data be transmitted to the asynchronous network and received therefrom. Another problem arises with synchronous networks in that a master clock is required to synchronize operation of all the synchronous network nodes to insure that all transmission paths and nodes serving data systems connected thereto transmit and receive data at synchronous transmission rates.